Connecting joints are usually formed when different building parts meet. Connecting joints are found in the region of connection to the inter-story ceiling, to the floor and to massive walls. Due to weight loading or thermal influences, the ceiling in buildings may be forced upward or downward. To prevent damage to the drywall, the upper connecting joint in this case is made as an expansion joint. Thus joints for creating discontinuities in building parts in order to prevent stress cracking are known as expansion joints. The ceiling profile is made in such a way that a relative movement between ceiling profile and the vertical wall components is possible.
In general, a channel profile constituting part of the studwork is fastened to the connecting building parts. The gypsum boards themselves are attached at a well-defined spacing to the connecting building part. Usually sealing of the system is provided in the gap between gypsum board and ceiling. For this purpose, either a suitable sealing compound is introduced or else the gap is filled with mineral wool and provided at the surface with a sealing layer. In both cases, the material present in the joint presents relatively strong resistance to movement, with the consequence that comparatively large joint widths are necessary in order to achieve adequate movement absorption.
In particular, sealing of the gap with sealing compound has some disadvantages. It is particularly laborious, and in the course of time the sealing tends to crack when overloaded. Furthermore, sealing can be performed only after the gypsum boards have been mounted, and it requires access to the finished drywall from both sides. Furthermore, this procedure is error-prone, since the user himself or herself must dose the correct quantity of material in order to seal the gap adequately. Above and beyond this, the drywall builder must make the width of the joint correspond to the material and expansion properties of the sealing compound. During installation of the sealing compound, nothing but the joint can be filled. During expansion of the gap, it must be ensured that the sealing compound adheres sufficiently strongly to the underlying surface and that it is able to absorb the tensile forces that develop. Frequently this not the case, and the danger exists that the sealing compound will become detached from the underlying surface or that the sealing compound itself will be overloaded and tear. In the case of a narrower gap, the sealing compound can be compressed to only a limited extent, because of its material properties, and the danger exists that it will be forced out of the gap if the joint is incorrectly dimensioned. Due to the limited expansion and compression capability of the sealing compound (max.+/−25%), it is very important to ensure adequately large dimensioning of the spacing between gypsum board and ceiling. This is frequently underestimated, and so adequate imperviousness often cannot be guaranteed during use of customary sealing compounds.
Some further approaches exist for sealing of joints, especially joint cords or joint sprays, which to some extent suffer from the same disadvantages as have been described for sealing compounds.
The object of the present invention is therefore to provide a joint-sealing tape that avoids the disadvantages of the known materials, that in particular is easier and safer to use, simplifies the mounting of further building parts and ensures good sealing as soon as it is applied as well as excellent imperviousness with maximum absorption of movement.
A further object of the present invention is to provide an arrangement that, in the event of fire, permits better sealing of the joint between two building parts, especially between a drywall and a connecting building part, such as a wall, a ceiling or a floor, and thus provides better and durable sealing against sound and/or smoke and if necessary better and durable fire protection, and can be mounted reliably and free of defects with little work effort.
This and further objects that will become apparent from the description of the invention hereinafter are solved by the present invention, as described in the independent claims. The dependent claims relate to preferred embodiments.